WANG Dongsheng1,2, ZHANG Jinchuan1,2, LIU Yang, LANG Yue1,2, LI Zhen1,2,
TONG Zhongzheng1,2, NIU Jialiang1,2, DING Wang3

（1. School of Energy Resources，China University of Geosciences，Beijing 100083;
2. Key Laboratory of Strategy Evaluation for Shale Gas，Ministry of Natural Resources，Beijing 100083;
3. Guangzhou Marine Geological Survey, Guangzhou 511458）

Abstract： Nitrogen (N) is an essential nutrient for all life on earth and has a significant and wide impact on the ecological environment. In recent years, the research on the nitrogen cycle has made significant progress in the fields of geobiology, geochemistry, marine science, atmospheric science and ecological health. Here, we review important advances in the nitrogen cycle in the marine system, summarize the impacts of modern humans on the nitrogen cycle in the marine system and corresponding feedbacks, and provide prospects for the future marine nitrogen cycle. Nitrogen isotopes (δ15N) is an important proxy for assessing the nitrogen cycle, and there is credible evidence that fluctuations in oxygen (O2) significantly contribute to the evolution of the nitrogen cycle. The marine nitrogen cycle is obviously closely related to biological and environmental evolution, consequently we focus mainly on the coupling of the global nitrogen cycle to the evolution of life and the environment during the Ediacaran-Early Cambrian, the Late Ordovician-Early Silurian, and Late Permian-Early Triassic intervals. Since the Anthropocene, human activities have greatly accelerated the emission of reactive nitrogen (Nr) to meet the needs of agriculture and industry, while the input of a large amount of Nr to the marine system has caused a series of causally related biogeochemical feedbacks, which have a strong impact on environmental changes, other element cycles and human health. With the continuous excessive input of Nr to the marine system in the future, the excess Nr emission has been regarded as one of the global environmental problems, and a series of key issues need to be studied urgently.

Key words：nitrogen cycle; nitrogen isotopes; the evolution of life; the evolution of environment; nitrogen budget; environment effect

EARTH AND ENVIRONMENT Vol.51, No.4, Tot No.354, 2023, Page 465